The late cosmologist/theoretical physicist, Professor Stephen Hawking and his daughter, Lucy, wrote the series of children book, "George's Secret Key", with the objective of introducing and explaining the concept of universe to the young ones.

​So far, there are 6 titles in the series (with the last one published in 2018 for which Lucy Hawking is the sole author):

Book 1: George's Secret Key to the Universe;Book 2: George's Cosmic Treasure Hunt;Book 3: George and the Big BangBook 4: George and the Unbreakable Code;Book 5: George and the Blue Moon;​Book 6: George and the Ship of Time.